油茶种间杂交叶表型的遗传变异分析

Analysis on genetic variation of phenotypic traits of leaves of F1 progeny from interspecific hybridization of Camellia

【目的】探究油茶杂交F1代叶片表型性状的分离规律和遗传变异特征。【方法】运用杂交F1代叶片质量性状香农-威尔多样性指数分析、数量性状离散描述及其相关性分析和聚类分析等数理统计法分析了攸县油茶×普通油茶‘华硕’种间杂交F1代47个单株的叶片表型(4个质量性状和12个数量性状)遗传多样性和遗传效应。【结果】1)叶表型的4个质量性状中,香农-威尔多样性指数的平均值为0.871,其中叶缘形态的多样性指数最高,为1.254;新叶颜色最低,为0.691。其中,叶形和叶背腺点有偏向母本的遗传趋势,而叶缘形态有偏离母本的遗传趋向。新叶颜色是绿色和红色趋近1︰1,分别是53.19%和46.81%,与母本相同的新叶颜色占46.81%,符合孟德尔遗传规律。2)12个叶片表型数量性状变异系数的平均值为17.75%,范围为9.55%~26.07%,经正态性检验后,发现其具有良好的正态分布趋势,符合多基因控制的数量性状遗传特征。12个叶表型数量性状在F1代的中亲优势率为-30.15%~25.93%。叶干质量、比叶重、叶型指数、叶长、叶面积和叶厚的中亲优势率为正,其中叶型指数和比叶重的平均值高于高亲值,叶鲜质量、叶宽、叶柄长、叶片含水率和叶顶角的中亲优势均为负,这些性状的平均值小于中亲值,其中叶鲜质量、叶宽和叶柄长趋中变异明显,存在于双亲之间,而叶片含水率和叶顶角的平均值小于低亲亲本,呈现出明显的趋小变异。3)16个叶片性状呈现错综复杂的相关性。4)聚类分析结果表明,聚类结果充分反映了各类群的综合特征。油茶种间杂交F1代在遗传距离为20.00处将其分为Ⅰ和Ⅱ类群。在遗传距离为10.0处,第Ⅰ大类群分为Ⅰ-a亚类和Ⅰ-b亚类。第Ⅰ大类群38个单株与母本攸县油茶聚在一起,形态表现与母本相似度更高,为偏母型。【结论】油茶种间杂交F1代叶表型性状变异丰富,其中12个数量性状表现出比较广泛的分离特征,4个质量性状均具有较丰富的多样性,这为下一步育种材料的利用提供了更广阔的空间。

【Objective】To investigate the separation and genetic variation of leaf phenotypic traits in F1 generation of Camellia yuhsienensis Hu(♀)×Camellia oleifera ‘Huashuo’(♂). 【Method】The leaf qualitativev traits of the hybrid F1 generation were analyzed by the Shannon-Will diversity index, quantitative description of quantitative traits, and correlation analysis and cluster analysis were used to analyze the genetic variability and genetic effects of leaf phenotype(4 quality traits and 12 quantitative traits) of 47 individual plants of F1 generation of Camellia.【Result】1) Among the four qualitative traits of the leaf phenotype, the average value of the ‘Shannon-Weinner’ index of five qualitative traits were 0.871, with the leaf margin morphology having the highest diversity index of 1.254 and the new leaf color having the lowest color of 0.691. Among them, the leaf shape and leaf glandular opaque have a genetic tendency biased toward the female parent, while the leaf margin morphology has a genetic tendency that deviates from the female parent. The color of the new leaves is green and red, which is close to 1:1, which is 53.19% and 46.81%, respectively. The new leaf color is the same as the female parent, accounting for 46.81%, which is consistent with Mendelian inheritance;2) The average coefficients of variation of the twelve quantitative traits was 17.75%, ranging from 9.55%-26.07%.After normality test, it was found to have a good normal distribution trend, which is consistent with the genetic characteristics of quantitative traits controlled by multiple genes. The ratios of heterosis value of mid-parents(RHm) of 12 leaf phenotypes were-30.15%-25.93% in the F1 generation. The leaf dry weight, specific weight of leaf, leaf type index, leaf length, leaf area and leaf thickness was positive, and the average value of leaf type index and specific weight of leaf was higher than high parental value, while leaf fresh weight and leaf width, petiole length, leaf moisture content and leaf apex angle were negative. The average value of these traits was less than the mid-parent value, and the leaf fresh weight, leaf width and petiole length were significantly different, which existed between the parents. And the average value of leaf water content and leaf apex angle is smaller than that of low parental parent, showing obvious small variation;3) 16 leaf traits present intricate correlations;4) Cluster analysis results show that Camellia hybrid F1 generations were divided into groups Ⅰ and Ⅱ at a genetic distance of 20.00. At a genetic distance of 10.0, the first large group is divided into Ⅰ-a subclass and Ⅰ-b subclass. 38 Superior Plants of the Ⅰ group are matroclinal, which are similar with C. yuhsienensis ‘Hu’ in morphological manifestation. The clustering results fully reflect the comprehensive characteristics of each group.【Conclusion】The phenotypic traits of F1 generation in Camellia hybrids were rich, and 12 quantitative traits showed extensive separation characteristics and four quality traits were rich in diversity.